Not only is that article not a study but rather a letter to the editor, but also in their last paragraph they explicitly state that ADE in SARS-CoV-2 has never been demonstrated in vivo. Here is the relevant quote from the letter:
>[...] Although this potential risk has been cleverly anticipated before the massive use of Covid-19 vaccines6, the ability of SARS-CoV-2 antibodies to mediate infection enhancement in vivo has never been formally demonstrated. [...]
A couple things though - the median age of Israel is higher than that of Palestine by a pretty large margin. Secondly, how can we be sure both places are testing at the same rate? For instance, the percentage of cases reported in Palestine VS Israel is smaller when adjusted for population size.
